Disclosure to Promote the Right To Information

Transcription

1 इ टरन ट म नक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. ज न1 क अ+धक र, ज 1 क अ+धक र Mazdoor Kisan Shakti Sangathan The Right to Information, The Right to Live प0र 1 क छ ड न' 5 तरफ Jawaharlal Nehru Step Out From the Old to the New IS 554 (1999): Pipe Threads Where Pressure-Tight Joints are Made on the Threads - Dimensions, Tolerances and Designation [PGD 20: Engineering Standards]! न $ एक न' भ रत क +नम-ण Satyanarayan Gangaram Pitroda Invent a New India Using Knowledge! न एक ऐस खज न > ज कभ च0र य नहB ज सकत ह ह Bhartṛhari Nītiśatakam Knowledge is such a treasure which cannot be stolen

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4 IS 554 : 1999 IS : Indian Standard PIPE THREADS WHERE PRESSURE-TIGHT JOINTS ARE MADE ON THE THREADS - DIMENSIONS, TOLERANCES AND DESIGNATION ( Fourth Revision ) ICS BE 1999 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI May 1999 Price Group 4

5 Engineering Standards Sectional Committee, LM 01 NATIONAL FOREWORD This Indian Standard (Fourth Revision) which is identical with IS0 7-l : 1994 Pipe threads where pressure-tight joints are made on the threads - Part 1 : Dimensions, tolerances and designation, issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Engineering Standards Sectional Committee and approval of the Light Mechanical Engineering Division Council. This standard was originally issued in 1955 and subsequently revised in 1964 and The third revision was harmonized with IS0 Standard by adopting IS0 7-1:1982. This fourth revision has been taken up to align it with the latest version of ts0 7-l which has been technically revised in The text of IS0 Standard has been approved as suitable for publication as an Indian Standard without deviations. In the adopted standard certain conventions are not identical to those used in Indian Standards; attention is especially drawn to the following: a) Wherever the words International Standard appear referring to this standard, they should be read as Indian Standard. b) Comma (J has been used as a decimal marker while in Indian Standards, the current practice is to use a full point (.) as the decimal marker. In this adopted standard, reference appears to one International Standards for which Indian Standard also exists. The corresponding Indian Standard which is to be substituted in its place are listed below along with its degree of equivalence for the editions indicated: International Standard Corresponding Indian Standard Degree of Equivalence IS0 7-2 : 1982 IS 8999 : 1979 Gauging practice for pipe threads where pressure-tight joints are required on the threads (first revision) (under preparation) Related A[ DITIONAL INFORMATION The verification of threads covered in this standard shall be done in accordance with IS 8999 : 1979 till the publication of its first revision. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 Rules for rounding off numerical values (revised). The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

6 IS 554 : 1999 Iso 7-1 : 1994 Indian Standard PIPE THREADS WHERE PRESSURE-TIGHT JOINTS ARE MADE ON THE TH~READS - DIMENSIONS, TOLERANCES AN-D DESIGNATION ( Fourth Revision ) 1 Scope This part of IS0 7 specifies the requirements for thread form, dimensions, tolerances and designation for jointing pipe threads, sizes l/16 to 6 inclusive, for joints made pressure-tight by the mating of the threads. These threads are taper external, parallel internal or taper internal and are intended for use with pipes suitable for threading and for valves, fittings or other pipeline equipment interconnected by threaded joints. An appropriate jointing medium should be used on the thread to ensure pressure-tight joints. NOTES 1 Parallel external pipe threads are not suitable as jointing threads. 2 For pipe threads where pressure-tight joints are not made on the threads. see IS0 228-l. 3 IS0 7-2 gives details of methods of verification of jointing thread dimensions and form and recommended gauging systems. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this part of IS0 7. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this part of IS0 7 are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 7-2:1982, Pipe threads where pressure-tight joints are made on the threads - Part 2: Verification by means of limit gauges. 3 Definitions For the purposes of this part of IS0 7, the following definitions apply (see also figures 3 and 5). 3.1 gauge diameter: Major diameter of the thread, whether external or internal. 3.2 major cone: Imaginary cone which just touches the crests of a taper external thread or the roots of a taper internal thread. 3.3 gauge plane: Plane, perpendicular to the axis of the taper thread, at which the major cone has the gauge diameter. NOTE 4 For external threads the gauge plane is located at a distance equal to the hominal gauge length from the small end of the thread. For internal threads the gauge plane is located at a distance of half-pitch behind the face of the threaded part. This is in order to give consideration to the start of the thread that has been removed by chamfering. 3.4 gauge length: On -an external thread, the distance from the gauge plane to the small end of the thread. 3.5 reference ptene: Visible surface of each of the internally and externally threaded parts, which facili- 1

7 IS 554 : 1999 IS0 7-1 : 1994 tates the reading of the gauge when the thread is inspected. For internal threads it is the face of the internally threaded part, for external threads it is the small end of the externally threaded part. 3.6 complete thread: That part of the thread which is fully formed at both crest and root. NOTE 5 When there is a chamfer at the start of the thread not exceeding one pitch in length, this is included in the length of complete thread. 3.7 incomplete thread: That part of the thread which is fully formed at the root, but truncated at the crest by its intersection with the cylindrical surface of the product. 3.8 washout thread; vanish thread: That part of the thread which is not fully formed at the root. P H h r D Dl D2 d Pitch Height of the triangle of the thread profile perpendicular to the thread axis = 0, P; height of the thread profile between rounded crests and roots perpendicular to the thread axis Radius of rounded crests and roots Major diameter of the internal thread at the gauge plane (gauge diameter - see 3.1) D - 1, P; minor diameter thread at the gauge plane D - 0, P; pitch diameter thread at the gauge plane of the internal of the internal Major diameter of the external thread at the gauge plane (gauge diameter - see 3.1) NOTE 6 The washout thread is produced by the bevel at the start of the threading tool. dt = d - 1, P; minor diameter ternal thread at the gauge plane of the ex- 3.9 useful thread: Complete thread plus incomplete thread, excluding the washout thread. d2 = d - 0, P; pitch diameter ternal thread at the gauge plane of the ex fitting allowance: Length of useful thread beyond the gauge plane of an external thread required to provide for assembly with an internal thread at the upper limit of the tolerance. NOTE 7 Internally threaded parts will have a sufficient length to accommodate the fitting allowance, except when they have a free run-out. See wrenching allowance: Length of useful thread which is provided to accommodate the relative movement between the end of the externally threaded part and the internally threaded part required for wrenching beyond the position of handtight engagement. 4 Symbols Rp Parallel internal pipe thread where pressure-tight joints are made on the threads Rc Taper internal pipe thread where pressure-tight joints are made on the threads R Taper external pipe thread where pressure-tight joints are made on the threads Tl T2 5 Tolerance on the ~gauge length of thread an external Tolerance for the position of the gauge plane on an internal thread Dimensions Pipe thread dimensions, in millimetres, are given in table 1. 6 Designation The designation of threads according to this part of IS0 7 shall consist of the following elements in the sequence given: 6.1 The description block shall be: Pipe thread 6.2 The International Standard number block shall be: IS0 7 2

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9 IS 554 : 1999 IS0 7-l : The individual item block shall be composed of: the hanks in such a manner as to give the same thread height h as for parallel threads. a) letter symbol(s) for type of pipe thread - the letter R followed by the letter p for parallel internal threads; - the letter R followed by the letter c for taper (conical) internal threads; - the letter R for external threads; b) the thread size, from column 1 of table 1. EXAMPLES The complete designation for a right-hand thread size 1 l/2: Internal thread External thread parallel Pipe thread IS07 - Rp 1 l/2 taper Pipe thread IS0 7 - Rc 1 l/2 ~favv~~ Pipe thread IS0 7 - R 1 l/2 Figure 1 - H = 0, P h = 0, P r-= 0, P Parallel thread 6.4 For left-hand threads, the letters LH shall be added to the designation. Right-hand threads require no special designation. 7 Thread design 7.1 Thread forms Parallel-thread The basic form of the parallel pipe thread shall be as shown in figure 1. The angle between the flanks, measured in an axial plane section, is 55. The thread profiles are rounded equally at crests and roots by circular arcs blending tangentially with the flanks Taper thread The basic form of the taper pipe thread shall be as shown in figure2. The taper is 1 to 16, measured on the diameter. The angle between the flanks, measured in an axial plane section, is 55, the flanks making equal angles with the axis. H = 0, P h = 0, P r = 0, P The thread profiles are rounded off equally at crests and roots by circular arcs blending tangentially with Figure 2 - Taper thread 4

10 IS 554 :1999 IS0 7-1 : Direction of thread helix Unless otherwise specified, the IS0 7-l thread shall be a right-hand thread. (See also 6.4.) 7.2 Thread lengths External thread The terms relating to the external taper pipe thread are given in figure3. The length of the useful thread, allowable in practice, is the sum of the lengths of the complete and incomplete threads, excluding the washout thread. The minimum length of the useful thread must be not less than the minimum gauge length plus the fitting allowance Internal thread The design of internally threaded parts shall be such that they can receive external threads up to the lengths given in column 16 of table 1. The minimum lengths &,,, of useful thread in the case of internal threads with free run-out shall be not less than 80 % of the values given in column 17 of table 1. (See figure 4.) 8 Gauging For the verification of pipe threads, the plug and ring gauges used shall conform to IS The gauging always relates to a reference plane of the threaded part to be verified (see figure 5). 9 Combination with fastening thread The combination of an external parallel thread G, toc erance class A or B in accordance with IS with an internal parallel thread Rp in accordance with IS0 7-l needs special consideration. When it is necessary to have this combination, the positive or negative tolerance of the internal thread to IS0 7-l shall be considered in the relevant product standards, where external parallel threads G are used. Such a combination of threads may not necessarily achieve a leak-tight joint. Reference plane Useful thread Allowance equivalent to positive tolerance on internal thread Figure 3 - Terms relating to external threads 5

11 IS 554 :1999 IS0 7-l :1994 Free run-out Free run-out Figure 4 - Internal threads with free run-out 1 Internal taper thread Chamfer Internal parallel thread Chamfer k-b Reference pkane p- Gauge plane..! Tolerance for position of gauge plane on internal threads i External taper thread Figure 5 - Illustration of internal and external pipe threads (position of gauge plane, reference plane useful thread) 6

12 IS 554 : 1999 IS0 7-1 : 1994 Annex A (informative) Bibliography Cl] IS :1994, Pipe threads where pressure-tight joints are not made on the threads - Part 1: Dimerr sions, tolerances and designation.

13 Bureau of Indian Standards BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote harmonious development of the activities of standardization, marking and quality certification of goods and attending to connected matters in the country. Copyright Be has the copyright of all its publications. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course 01 implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director (Publication), BIS. Review of Indian Standards Amendments are issued to standards as the need arises on the hasis of comments. Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if ~the review indicates that changes are needed, it is taken up for revision. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of BIS Handbook and Standards Monthly Additions. This Indian Standard has been developed from Dot: No. LM 01(0368). Amendments Issued Since Publication Amend No. Date of Issue Text Affected Headquarters:. BUREAU OF INDIAN STANDARDS Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi Telegrams: Manaksanstha Telephones: , , (Common to all offices) Regional Offices: Central Eastern : Northern : : Manak Bhavan, 9 Bahadur Shah Zafar Marg NEW DELHI l/14 C.I.T. Scheme VII M, V.I.P. Road, Maniktola CALCUTI-A SC , Sector 34-A, CHANDIGARH Southern : C.I.T. Campus, IV Cross Road, C!IENNAI Western : Branches : Manakalaya, E9 MIDC, Marol, Andheri (East) MUMBAI AHMADABAD. BANGALORE. BHGPAL. BHUBANESHWAR. COIMBATORE. FARIDABAD. GHAZIABAD. GUWAHATL HYDERABAD. JAIPUR. KANPUR. LUCKNOW. NAGPUR. PATNA. PUNE. THIRUVANANTHAPURAM. { { Telephone , , , , , p , , Printed at Simco Printing Pma, Delhi India